A Good Big Brother
by MadHatterLilith
Summary: Killua didn't know before what a good big brother really was until he met his second family. Centered on Leorio and Killua as a family, trigger warnings inside. M to be safe.


**Some slight mentions of abuse, mental health shame, and trauma, specifically panic attacks. Tried to be vague enough to not be too triggering but if it's a trigger of yours, I don't recommend you read this. Stay safe y'all.** **Feel like this doesn't really need to be said but not a pairing fic! Just family fluff. I just like the idea of Leorio being an older brother to them because it's basically canon. Tried to quote Illumi but forgot the exact quote. Let me know what he actually said and your thoughts, I guess?**

 _Good big brothers don't try to kill you._

Really, to anyone else, that was obvious. But in Killua's family, it seemed natural. Sure, Illumi wouldn't actually kill him, but he had no reservations in targeting Alluka, their baby sister. If not for her power, for Nanika, would she already be dead? Or if not for Nanika, would Alluka be able to live like a normal girl?

Was he being a bad big brother too by wishing for that for even a second?

 _They do argue with you though._

"Hey, Killua! You ate the last slice, didn't you?! I told you I was saving that!" Leorio snapped, finding the pizza box empty. Gon laughed, making no effort to scold Alluka as she peeked at Leorio's cards. No wonder she was on a winning streak!

"There's no saving when it comes to food, idiot." Killua jeered, giving his sister a thumbs up. Leorio was so dumb sometimes; Alluka might look like a sweet girl but look who taught her to play cards! It was like he didn't know Killua at all.

"Argh! You brat!"

 _Good big brothers don't beat you, whip you, or break you._

Illumi's training was harsh, but it was, his family told him, for his own good. Somehow, before he knew it, the pain was so natural that it didn't hurt so bad. Somehow being afraid, especially of those soulless eyes, was normal. He was used to it.

Milluki's whip stung, but he deserved it. He disobeyed his family. He turned his back on them and all they did for him. He disappointed them. No, he decided, those were excuses. He deserved it because he couldn't fight even if it meant he could save Gon.

 _But they will get onto you sometimes._

"Killua, you made another one of my patients freak out!" Leorio fussed. "Stop telling those kids all those scary stories! Don't you have any child friendly ones?"

"How about that tower in the Hunter Exam?" Killua asked, grinning. Honestly, none of the "child friendly" ones were interesting. None of them that fit Leorio's definition of "child friendly" anyway. "Like when I ripped that guy's heart out and you touched that chick's—"

"NO."

 _Good big brothers don't stop you from being yourself._

Alluka was a girl; it was something she just always knew and never doubted. And Killua didn't question it either when she told him. After all, she'd know best, right? But when she tried to tell Milluki or Illumi, they ignored her and continued to call her their brother instead. Soon, they decided she wasn't even their sibling anymore; she was just a "thing from somewhere else." At some point, without even realizing it, Killua didn't think of her either. Was it really Illumi's needle? Or was he really that caught up in himself?

Killua knew early in his life that he didn't want to live like his father, grandfather, and all the other family heads before him. Though he admired his father and grandfather, he wanted something different. He wanted to make friends; he didn't want to be alone anymore.

 _"Someone like you could never have friends."_

But Illumi said it was impossible for him; it was impossible because that's not who he was.

 _They might go a bit overboard though._

Gon introduced him to everyone he knew and strongly encouraged them to befriend Killua, going on at length about how great his best friend was, much to Killua's embarrassment. Leorio backed him up on it as did Alluka. It felt like his family was setting him up with friends, and man, was it embarrassing!

Even before they started with her treatments and researching hospitals for her surgeries, they accepted Alluka with a huge fuss. Honestly, if Leorio didn't stop with all the positive, supportive messages soon, he was going to strangle him with one of the cute dresses he bought for his sister. Support was great but sometimes Leorio was over the top and made a big fuss about something that just seemed totally natural to to both him and Alluka. It made them both feel like it had to be a bigger deal than they were making of it simply because Leorio was so happy for her.

It was embarrassing but he was glad they cared so much.

 _Good big brothers don't shame you in your moments of weakness._

Illumi's eyes and voice, certain painful stimuli from his training, being told that someone was disappointed in him... sometimes it felt like he was being crushed, trapped by those things. He was caged by something only he could see or feel and desperately wanted his freedom. He wanted it so bad it hurt; it hurt to even breathe.

The few times he showed this shameful side of himself to his family, more because the attacks were sudden and unexpected than anything else, the looks on their faces, save his Mother's panic, were unsympathetic disappointment. He had to be tougher than this to be the future head of the family. They expected better of him; this was shameful and weak behavior.

So no matter how much it hurt, he hid and faced it alone.

 _But they won't let you be alone either._

The first time his friends found out about his attacks, he was ashamed beyond belief. Great, they knew that he was actually weak! There was no way they'd want to stick by someone as pathetic as him, he thought. But they did.

Kurapika understood what he needed in that moment. He had the attacks too but where Killua saw the disappointed stares of his family, Kurapika saw the unapologetic smiles of the thieves who stole his family's lives. Gon didn't really know what to do but he didn't leave Killua's side and even tried to distract him from the source of his sudden anxiety and stress. He found out later that Leorio suggested that and he took care of Killua afterwards.

"Don't push yourself." He'd told him, a rare soft moment between the two. "Your mental health is nothing to be ashamed of or ignore. I can't tell you to just let go of everything now; I know it's not that simple. But focus on living your life for yourself, not your family."

He wondered if Leorio had the same issues once.

 _Good big brothers don't make you afraid..._

They don't make your blood run cold, your heart pound in your ears, or your hands shake. They don't make you hold your breath and stiffened up like a statue. They don't cause your knees to shake and buckle.

They don't leave lasting scars on your heart.

 _...they make you embarrassed, happy, and irritated._

Leorio had a habit of flirting with shop attendants on the rare occasion that they shopped together. Maybe his face and personality weren't terrible but whatever book he got his pickup lines from needed to be collected and burned as a public service. Jeez, the day a girl fell for one of those dumb jokes was the day Killua would finally give in and start the homeschooling program his patients suggested. No that he needed it...Assassin homeschooling was more thorough than one might think.

He remembered their birthdays and celebrated them on the days, even if they weren't there. He'd send them cards wherever they were, telling them to come home soon to celebrate as a family. Even penny pinching, struggling small town doctor Leorio would go all out for him, Alluka, and Kurapika, the kids who never got to have parties like that in their youths. Sure, Kurapika rarely showed up or stayed long but the sentiment was enough. On Gon's birthday, Mito took over and forced Leorio into a supporting role instead. But it still brought him near tears each time. Not that he'd ever let it show.

 _Good big brothers aren't just your blood..._

Illumi and Milluki were his blood kin. It was from them that he learned what a big brother should be like. From Illumi, he learned that a big brother was a stern guide who'd resort to any manipulative method or force to keep you in check. From Milluki, a guidepost in the opposite direction, a hateful person who'd punish you for any mistakes or wrongs.

But that wasn't what a good brother was.

 _...but those who help you overcome it._

Kurapika was his family, even as distant as he sometimes was, partly to protect them and partly to protect himself. He was a good big brother who understood his pains and fears.

As was Gon, his best friend. There was no word for their bond, he felt. Brother, friend...nothing felt right, really. Nothing but family felt like it was strong enough to describe the connection between the two of them. Maybe he wasn't exactly an older brother, but he was something.

And then there was Leorio, his older brother. He showed him that there was nothing wrong with struggling, with being someone his family didn't expect, or with wanting to be a kid sometimes. Aside from Gon or Alluka, he was probably his strongest bond, his closest friend. Not that he'd ever tell the doctor; that wasn't how it worked with them.

 _Besides, it didn't really need saying_.

 **Sorry for writing this; it's not all that great and probably done before. Still, the main four as family gives me life.**


End file.
